Tour de France: Ireland's Dan Martin finishes third behind Sagan and Matthews after stage three
Team Sky's outstanding start to the Tour de France got even better in Longwy as Chris Froome joined Geraint Thomas at the top of the standings after world champion Peter Sagan won stage three.
Bora-Hansgrohe's Sagan beat Michael Matthews of Team Sunweb and Quick-Step Floors' Dan Martin in an uphill sprint, but with Thomas and Froome crossing the line in eighth and ninth they took control of first and second place in the general classification.
Thomas leads by 12 seconds from Froome, with Australian Matthews third on the same time and Sagan fourth, a further second back.
"It's the best start we've ever had," Thomas said. "It is still a fight but it means we have the freedom to ride up there."
The 212.5km stage from Verviers took the riders on a lap of the Spa-Francorchamps Formula One circuit before they passed through Luxembourg and into France for the first time this year.
But the battle for victory was always expected to come down to the final climb, the Cote des Religieuses.
Sagan was the clear favourite and duly delivered despite pulling his foot out of his pedal as he tried to launch his sprint.
"You don't have time to think," he said of that moment. "You just have to do."
Sagan came to the fore after BMC's Richie Porte, seen as Froome's main rival in the race, launched his own attack 800 metres from the finish.
"It wasn't (premeditated) at all but the guys put me in a fantastic position," said the Australian, who sits 20th, 47 seconds down on Thomas.
"It felt good but I knew when I saw that 500m to go sign that it was a bit too far for me...
"It was just good for the confidence to have a bit of a crack there."
Sky had been happy to let Porte exert himself, confident others would do the work to chase him down.
"We were not too stressed about it," Thomas said. "We knew Sagan and some other guys would want to ride for the stage and would cover it."
The little show of force has nevertheless made Porte the favourite for stage five to La Planche des Belles Filles, the first serious climb of this year's race.
But Froome, who took his first career Tour stage win on that climb in 2012, warned his friend and former team-mate he would have it all to do to take yellow off Thomas.
"He'd have to make up 35 seconds on me and 45 seconds on Geraint," he said. "That's certainly going to take some doing on a six-kilometre climb."
For Martin, third place will come as a confidence boost as he bids to stay with the general classification contenders.
Four bonus seconds for a podium finish move him up to 15th place, 43 seconds down on Thomas.
The Irishman posted a picture on the finish on Instagram and wrote: "I expected to post a photo of Spa Francorchamps Circuit as my highlight of today. Then this happened. Unexpectedly found my sprint legs."
Sitting one-two at the top of the overall standings is a fine way for Team Sky to end a day which began with more rumblings about the skinsuit they wore in the opening time trial in Dusseldorf.
Team Sky finished with four riders in the top eight on Saturday, with Thomas winning to take yellow, but rival teams claimed their kit violated rules on aero design.
The team have worn the kits - which were cleared by the race jury - in other events this year without complaint, and Sky team principal Sir Dave Brailsford said he found the ongoing discussion 'funny'.
"I'm surprised because we've ridden in that skinsuit since May," he said. "Nobody has mentioned it. No other team has raised it until now.
"If they are that slow picking it up, they should have a look at their own performance - if another team is doing something new, I will know within 24 hours because we monitor the other teams.
"We get derided about marginal gains, but when it does work we get derided even more. It's all part of the fun, though."
But the team were less amused when they picked up the morning edition of L'Equipe as the French sports daily splashed the accusations on the front page.
Team Sky's riders have faced abuse from Tour crowds in the past and, given the tense security around the race, there was concern the coverage could provoke further incidents.